Optical communication connectors having a structure in which a light-emitting element and a light-receiving element are optically connected to two optical fiber cables have been widely known. Single-core directional optical communication connectors having a structure in which a light-emitting element and a light-receiving element are optically connected to a single optical fiber cable have also been known (for example, see PTL 1).
The single-core bidirectional optical communication connector disclosed in PTL 1 includes a substantially Y-shaped optical waveguide and an optical wavelength filter disposed in one branch of the optical waveguide. An optical filter transmitting light of emission wavelength and blocking light of reception wavelength is used as the optical wavelength filter.
The single-core bidirectional optical communication connector disclosed in PTL 1 includes an optical connector housing having the same structure as the optical connector housing of the two-core optical communication connector used before the single-core bidirectional optical communication connector. That is, the single-core bidirectional optical communication connector includes an optical connector housing having a structure in which the attachment and detachment direction of an optical fiber cable is perpendicular to the direction in which a light-emitting element and a light-receiving element are arranged (includes an optical connector housing having the same basic structure as known in the related art).
PTL 2 and PTL 3 disclose techniques of a single-core bidirectional optical communication module including an optical filter transmitting a first optical signal and reflecting a second optical signal.
In the single-core bidirectional optical communication module disclosed in PTL 2, a light-emitting element and a light-receiving element are arranged so that the optical axes are orthogonal to each other (orthogonal arrangement). The optical filter is disposed at the orthogonal intersection position of two optical axes. The optical filter is disposed at the orthogonal intersection position in a predetermined space by the use of a dedicated component.
The single-core bidirectional optical communication module disclosed in PTL 2 has a problem in that the size of the module including a circuit part (device) increases (whereby the single-core bidirectional optical communication connector also increases in size), since the light-emitting element and the light-receiving element are disposed to be orthogonal to each other. Since the light-emitting element and the light-receiving element are disposed to be orthogonal to each other, there is a problem in that the single-core bidirectional optical communication module cannot be assembled into the optical connector housing having the structure according to the related art. In addition, since the optical filter is disposed at a predetermined position in a predetermined space, a dedicated component is necessary. Since it is also necessary to guarantee an assembly space for the dedicated component, there is also a problem in that the size of the module increases as described above. In order to dispose the optical filter at a predetermined position in a predetermined space, it is necessary to perform a highly-precise positioning process. Accordingly, there is also a problem in that the manufacturing difficulty increases.
The single-core bidirectional optical communication module disclosed in PTL 3 has a structure in which the attachment and detachment direction of the optical fiber cable is parallel to the direction in which a light-emitting element and a light-receiving element are arranged (that is, a structure in which the optical axes of the light-emitting element and the light-receiving element are orthogonal to the optical axis of the optical fiber cable). The single-core bidirectional optical communication module disclosed in PTL 3 includes an optical path changing component (optical member) formed of a resin. The optical filter is fixed to the optical path changing component with an adhesive.
The single-core bidirectional optical communication module disclosed in PTL 3 has a problem in that it cannot be assembled into the optical connector housing having the structure according to the related art. Since the optical filter is bonded to the optical path changing component, there is also a problem in that the optical filter may be destroyed due to the difference in the thermal expansion coefficient between the materials thereof.